Diesel fuels are traditionally hydrocarbon liquids obtained by the fractionation and refining of petroleum. The cost of petroleum crude oil has been rising very rapidly. The rather drastic increases in crude oil costs have placed a severe burden upon many commercial and industrial operations, using substantial amounts of diesel fuel.
The total amount of diesel fuel used each year in such operations is enormous, with for example, diesel fuel consumption in the United States alone amounting to more than 10 billion gallons in 1980. The rising costs of diesel fuel, coupled with the inevitable depletion of supply, have created serious concern. Thus, there is a real and continuing need for an alternative source of diesel fuel which is available without import dependency, and which can be generated from a renewable resource.
In seeking alternatives to petroleum based diesel fuel, one primary target of investigation has been alcohols. For example, methanol has been a prime object of investigation. However, methanol has met with only limited success as a substitute, because it is currently made on a large scale commercial basis exclusively from natural gas or petroleum. Methanol cannot therefore be regarded as other than in limited supply in the same way as natural gas and petroleum.
In the past, there has been some discussion of use of glycerides as a fuel substitute, that is, vegetable oils such as castor oil, sunflower seed oil and rapeseed oil, see, for example Journal of American Oil Chemists Society, Vol. 57, No. 11, November 1980, entitled "Searching for New Diesel Fuels". However, while vegetable oils such as those described in the referenced article do avoid petroleum as a supply source, there are other potential problems. That is, the use of primary human food products for fuel constitutes a sort of competition between use of these as foods or as energy sources for operation of diesel engines. Nevertheless, since we have not yet reached the limits of our agricultural capacity to produce renewable crops such as soybeans, sunflower seeds, rapeseeds, castor beans and the like, the possible use of vegetable oils derived from these seeds for fuel is realistic.
Accordingly, a primary object of this invention is to produce an improved diesel fuel which is wholly prepared from non-petroleum based materials.
Another objective of the present invention is to prepare a diesel fuel from entirely renewable resource materials, all readily available without dependency on foreign imports.
A further object of this invention is to provide a diesel fuel composition which is prepared exclusively from industrial waste materials by a fermentation process.
A yet further objective of the present invention is to produce a diesel fuel composition which is a blend of fermentation produced butanol and vegetable derived glycerides.
An even more particular objective of the present invention is to produce a diesel fuel composition comprising a blend of fermentation produced butanol with a blend of fermentation produced glycerides.
And yet another objective of the invention is to provide a process for making a diesel fuel composition which comprises fermenting cellulosic substrate materials, in the presence of a culture of butanol forming micro-organisms; and growing a culture of glyceride accumulating micro-organisms under suitable culture conditions, followed by extracting both the butanol and the glyceride; and thereafter blending both to provide a diesel fuel.
The method and manner of accomplishing each of the above objectives, as well as others, will become apparent from the detailed description of the invention which follows hereinafter.